The premise sounds almost too good to be true: Taking a nap in the middle of the day might end up making you more productive. Of course, avid nappers will attest to feeling better after taking such a break, but members of that group are naturally more likely to believe in the power of naps.

Similarly, people who have chosen not to nap -- from fear that the downtime will eat into their working hours -- will naturally be inclined to believe that naps are a waste of time.

So, where does the truth lie?

Sleep and productivity

It should come as no surprise that sleep and productivity are tightly interconnected. If you get the recommended amount of sleep each night (seven to nine hours for most adults), you'll be more alert, more focused and equipped with a better memory.

According to a study fueled by data from the American Time Use survey, healthy sleep patterns are correlated with productivity in the form of higher wages. Sleeping just one additional hour every week correlates with an increase in short-term wages of about 1.5 percent, and long-term wages of about 4.9 percent. That's a massive jump just for taking one extra hour-long nap a week.

The evidence for naps

Scientists still don't have a firm grasp for exactly how naps function in relation to our sleeping habits, but there is some evidence that links naps, specifically, to working benefits. For example, one study by the University of Michigan randomly assigned 40 adult participants to two groups. One group took a 60-minute nap, and the other watched a nature video; for the "napping" group, the researchers found the following results:

Less impulsive behavior. Napping participants were less likely to engage in impulsive behaviors, such as engaging with distractions or moving off-task.

Higher tolerance for frustration. When trying to complete a difficult puzzle, napping participants were less likely to exhibit signs of frustration and other negative emotions.

Sleep has been shown to be a facilitator of learning and long-term memory: Taking an extended nap midday can help you remember things you've recently learned. Also,an extended midday nap has been shown to boost mood and alertness -- even more than a dose of caffeine.

The downsides of napping

Not all the evidence for naps is positive, however. If you aren't careful about how you nap, you could end up with sleep inertia. This happens when you wake up at an inopportune time in your sleep cycle, so your body wakes up incompletely and unexpectedly. As a result, you feel groggy and drowsy, and more tired than you did before you took the nap in the first place.

There's also some limited evidence that midday naps can be harmful for large-scale productivity. Spain, for example, is famous for its workday centerpiece: a midday break called a siesta, after which workers return to their jobs and remain there into the evening hours.

This working schedule was recently the center of some controversy, when politicians noted that Spaniards work more hours and are still less productive than workers in neighboring countries with a conventional 9-to-5 schedule. This evidence is limited, and was not formally studied.

How to nap effectively

Overall, naps can be a good thing for your productivity -- and your health -- but there are some precautions you'll need to take to get the right benefits:

Get the timing right. Napping after a long day of work, when you only have 30 minutes of work left, probably won't help you. If you're going to nap, make it a midday occasion, to make the most of your post-nap energy boost.

Set an alarm. If you sleep too long, you'll experience sleep inertia. If you don't sleep long enough, you won't get the benefits of the nap. Aim for between 60 and 90 minutes of sleep time, but feel free to experiment. What works for you may be different from what works for others.

Get quality sleep. If you're going to sleep, sleep well. Find a comfortable, dimly lit area that won't interrupt you with noise or distractions. Take off your shoes, clear your mind and ask not to be disturbed.

You don't need to nap every day to see an increase in productivity, nor does napping guarantee higher productivity. Try using napping as a tool to make up for sleep deprivation you may face on a regular basis, and strive for all-around healthier sleep habits.